The other day, I popped into an energy shop. I needed three bags of electricity and a punnet of gas. Then, because I'm an eco kind of girl, I picked up a bottle of wind as well.

Came to 12 quid! Can you believe it? I dumped the lot on the floor in a huff and went to Tesco, where they do a "gas family pack" for a fiver. It's more than I need, it's wrapped in nasty plastic and I'm not at all sure it's organic – but you can't argue with a massive price difference.

That didn't really happen. Or, at least, it only happened in the mind of Chris Huhne, who (according to the Times) has complained that people "do not bother" shopping around for energy supplies. So we only have ourselves to blame if we're going skint on the costs.

People, Chris Huhne reportedly opined, "spend less time shopping around for a bill that's on average more than £1,000 a year than they would shop around for a £25 toaster".

But let me ask you, Mr Huhne, at the risk of sounding like Lewis Carroll: what is the difference between gas and a toaster?

If toasters were invisible, and not stocked on the high street but ordered by phone, on a promise to pay whatever I happened to be charged three months later according to an incomprehensible retrospective calculation of how much toast I'd eaten, provable only by a series of numbers which bore no evident relation to bread or Marmite, I wouldn't shop around for those either. Because it wouldn't really be possible.

Chris Huhne later denied suggesting that people are lazy, criticised the "predatory pricing" of energy companies and called for fairer, clearer competition. But that still leaves us punters in a surreal world of imaginary gas shopping, haggling over the price of the theoretical, predicted and unseen – with Ronnie Barker selling fork handles behind one counter, Michael Palin crooning: "Beautiful plumage, the Norwegian Blue" behind another, and Reece Shearsmith hissing: "This is a local shop for local people!" from the doorway.

I've been trying to get someone from npower on the phone for months to explain why they sent me a bill for £900 in January, based on figures they claimed their visiting meter reader had taken on 26 December – when I was at my mother's house, nobody was home in my flat and the meter readers aren't at work.

If an off-duty gas man took the trouble to break into my flat on Boxing Day and file a reading, I wish they'd come out and say so. I'd be quite impressed with the commitment.

I won't bore you with the saga of their multiple failed promises to investigate and call back. The gist is: after a series of red warning letters, I paid the money to avoid being cut off – and got another bill for £900 three weeks later.

Asked to explain why a person living alone in a two-bedroom flat would accrue such massive energy bills (suggesting that a family of four, living in a house, would have a choice between remortgaging or bathing in a tin bucket in front of an open fire), they advised that I unplug the TV at the mains when not watching it.

When I say "they", I mean, of course, the series of anonymous people in Newcastle or Newport (or New Delhi) who answer the phone after 20 minutes of blood-boiling button-pressing and refuse to offer a direct line so you can speak to the same one again – rather than the twinkly and accountable shopkeepers of free-market fantasy.

Last week, thanks to the serendipity of internet blogs and links, I read an extract from a science textbook that's on the syllabus of an American Christian school.

"Electricity is a mystery," explains the tome. "No one has ever observed it or heard it or felt it. We know that it makes light bulbs shine and irons heat up and telephones ring. But we cannot say what electricity itself is like. We cannot even say where electricity comes from. All anyone knows is that electricity seems to be everywhere and that there are many ways to bring it forth."

You may laugh. You may groan. You may fear for the future of American schoolchildren. Me, I'm just reminded of my conversations with npower. Their representatives say much the same thing.

Sadly, alternative suppliers all spout the same waffle (easily done when we can't see the physical "product" or measure it without their meters) so there's no useful comparing to be done. What I was surprised to see go unobserved, in the reporting of Chris Huhne's shopping-around plans, is how Tory it is to assume there ever would be. So much for the balancing hand of the Lib Dems on the coalition tiller: while we're all out here seeing quite clearly that privatisation made everything worse, they're busy arguing for more private companies and greater individual choice. It's so market-eager, so decentralised, so big society. And it's a handily neat example that the principle doesn't bloody work.

Being offered a choice of suppliers (in this case for energy, but it will be the same with education and healthcare) is supposed to devolve power on to the "consumer": out there we bustle, seizing our own destinies, controlling our own environments, forcing candidates to get competitive with quality and pricing. What happens in practice is that we find no humanly possible way of doing that and end up feeling more impotent, not less. Our fear of injustice beyond our control gets bigger, not smaller. If we can't control the supply method, the costs or the calibre, and the government won't, then nobody's answerable at all. It's a competition that doesn't really exist.

It is – like Einstein's, we've suddenly heard – a theory of relativity that falls apart on inspection.